A medical power of attorney gives someone else the right to make decisions about their medical care on their behalf.
A medical power of attorney is usually a kind of durable power of attorney - meaning that it will last after the principal has been incapacitated. According to Section 166.152(g) of the Texas Health and Safety Code, it lasts until:
In the event that you cannot make decisions about your own medical care, this document would allow someone you trust to make those decisions for you. It is a common part of later-life planning and legal preparations for people with disabilities.
Note that a medical power of attorney differs from a "living will," which allows you to state what medical procedure you do and do not want performed. For example, a living will would allow you to tell doctors that you do not want to receive a blood transfusion. A medical power of attorney does not discuss specific procedures but instead gives someone else the authority to make decisions about those procedures for you.